Edge Metal-Semiconductor-Metal Junction THz Detector with Giant Responsivity

Abstract

Researches on terahertz (THz) detectors have been conducted extensively for various applications including security, wireless communications, and medical imaging and treatment. In case of metal-oxide-metal (MOM) diode THz detectors, a small junction area is desirable because the detector response time can be shortened by reducing it. An edge metal-semiconductor-metal (EMSM) junction has been developed with a small junction area controlled by the film thickness of metal electrode. This device structure allows the very fine tuning of junction area without any nanoscale patterning. The voltage response of the EMSM THz detector is dependent on the polarization angle of the THz wave and the responsivity is very high (~ 1,889 V/W) at 0.4 THz without any antenna and signal amplifier. The EMSM junction structure can open up a new way of fabricating the diode THz detector that can have extremely small junction area.